Loud speaker



Sept. 1 1, 1928;

N. BALDWIN LOUD SPEAKER Filed June 14, 1926 Jrro 0 \M/ 1 n a N M 4 N x 2 M 4 w v v v m v x 1 8 7 ,L

Patented Sept. 11, 1928.

UNITED STATES ,NATHANIEL BALDWIN, OF EAST MILL CREEK, UTAH.

LOUD SPEAKEB.

Application .flled .Tune 14, 1826. -S.eria1 The present invention appertains to loud speakers and particularly to those in which large diaphragms are used without horns.

The principal objects are to provide a sim ple-and efiicient means to increase the force of the operating armature upon the diaphragm and to increase the freedom of operation of such diaphragm. I attain these and other objects by the mechanism illustrated in the accompanying drawing in whichFigure 1 is a section of the instrument embodying the essential features of the invention.

Numeral 1 designates a housing in which the working elements are mounted. The ring 2 secured to the inner surface of this housing near one end and the gasket ring 3 made of soft rubber or other suitable material form r a seat for the diaphragm 4. This'diaphraghn made of paper or other light membrane has a special cuspoidal curvature as shown and is adapted to withstand pneumatic pressure within the housing 1, which pressure against the diaphragm is counterbalanced by the tension on the connecting link 5 which may be a cord or a'rod having a flexible connec tion to the operating element. A disc 1 made of stiff light material may be used .0 advantage to re-enforce the middle part of the diahragm. .A threaded ring 6 clamps the edge of the diaphragm against the gasket 3 and seals the joint between the diaphragm and housing.

A stream of gas, preferablv some gas lighter than air such as hydrogen isladmitted t0 the chamber thus termed through the tube 7 and escapes through the opening 8. The valve 9 is acted upon by a spring so that a certain pressure suitable for the diaphragm 4 is requi red to open it, andthis pressure will be accurately maintained within the housing 1.

The operating element consists essentially of an armature 10, fulcrumed within the spool 11 containing the actuating winding, pole 'piecds 12, 12, magnet 13 and cushion 14.

Special shaped fulcrum points 15 fixed within the spool 11 fit into special shaped sockets formed in the armature 10, in such way that the fulcrum will stand an end pull on the armature, or a side pressure, and the 5-." armature is placed on an angle-exceeding ninetydegrees with the connecting link 5 thus providing a mechanical power on the principle of the toggle joint. It will be seen that bet ween the limits of ninety degrees and .5 one hundred eighty degrees the greater the angle the greater the mechanical advantage,

N1 and the anglZ of greatest efliciency is found experimentally for the particular diaphragm to be used.

The pressure of the gas within'the housing.

' most of its acoustic energy to be impressed upon the open air. 1

The magnet 13 with the other operating parts is mounted within thehousing -1 upon the block 17 and the housing 1 is mounted upon the base plate 18.

One of the prlncipal features of the present invention is the armature disposed at an obtuse angle with the connecting link and it is understood that this combination may be used in connection with sound producing elements other than diaphragms such as sound boards,

pneumatic valves or microphones as indicated in the appended claims.

I claim:

1. A loud speaker comprising a diaphragm, an electrically operated armature mounted upon a fulcrum, and a link flexibly connected to said armature to transmit the movement of said armature to said diaphragm, said armature beingdisposedito said link at an angle substantially greater than ninety degrees.

2. A lopd speaker comprising a diaphragm, an electn cally operated armature mounted upon a fulcrum, and a link flexibly connected to said armature to transmit the movement of said armature to said diaphragm, said armature being disposed to said link at an angle substantially greater than ninety degrees and substantially less than one hundred eighty degrees.

3. A loud speaker comprising a diaphragm,

an electrically operated armature mounted upon a fulcrum, a link-under tension and flexibly connected to said armature to transmit the movement of said armature to said diaphragm, said armature being disposed to said link at an angle substantially greater than ninety degrees and substantially less than one hundred eighty degrees, and a resilient member at one end of said armature to balance the tension of said link.

4. A loud speaker comprising a diaphragm having a light gas on one side and the other side exposed to the open air, an electrically operated armature mounted upon a fulcrum and a link flexibly connected to said armature to transmit the movement of said armature to said diaphragm, said armature being disposed to said link at an angle substantially great. er'than ninety degrees and substantially less than one hundred eighty degrees.

5. A loud speaker comprising a diaphragm having a light. gas under excess pressure on one side and the other side exposed to the open air. an electrically operated armature mounted upona fulcrum, a linkflexibly connectedto said armature and under tension to counterbalance the excess pressure on said diaphragm and to transmit the movement of said armature to said diaphragm, said armature being disposed to said link at an angle. substantially greater than ninety degrees and substantially less than one hundred eighty degrees, and a resilient member at one end of said armature to balance the tension of said link.

6. A loud speaker comprising a sound pro ducing element, an electrically ope-rated armature mounted upon a fulcrum. and a link flexibly connected to said armature to transmit the vibration of said armature to said sound producing element, said link being disposed to said armature at an obtuse angle.

7. Aloud speaker comprising a housing. an electrically operated armature, a diaphragm co-operating with said housing to form an enclosed space, said diaphragm being actuated by said armature, and a gas lighter than air in the space enclosed by said housing and said diaphragm, v

8. A loud spea'ker comprising a housing, an electrically operated armature, a diaphragm eo-operating with said housing to form an en closure space, said diaphragm being actuated y said armature and a gas lighter than air under -modified pressure in the space enclosed by said housing and said diaphragm.

9. A loud speaker'comprising a sound producing clement. an electrically operated armature, and a link flexibly connected to said armature to transmit thevibration of said armature to said sound producing element. said link being disposed. to said armature at an obtuse angle.

NATHANIEL BALDWIN; 

